Don,
the piece is wired into the harness and has two pairs of black wires approx 16-18ga one pair of which goes to the overboost switch and the second pair is buried in the wiring bundle and runs under the intake. May shoot to the wur, I'll have to track it and report back...

Weird....the overboost pressure switch takes only a single wire and the switch is normally closed to complete the ground circuit so the pumps will run. Maybe your relay is a low-cost get-around of the higher cost yellow boost relay.

__________________Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.